The amount of STEEM in the rewards pool sounds about right. Where are you getting your number for the number of authors though? Also are they active every day?
The platform is not designed to give every active author a lot of money. Some authors will make more than others. It also depends on a lot of factors, including the quality of the author's content, and their social networking.
@bitgeek is putting out a report that has conflicting numbers with what I have stated, when I get time I will reconcile my numbers.
https://steemit.com/steemit/@bitgeek/payout-stats-report-for-26th-september-2017--part-i
@elyaque is the report I use.
https://steemit.com/steemit/@elyaque/daily-steem-report-september-24th-steem-1-07usd-767-new-accounts
I don't know if posts is comments and posts, or not.
I just want to know how much is on the table for each post each day so that we can know how many people are being forced to zero by those that trend.